Eldorado Touring V8-4.6L VIN 9 (1998)
Powertrain Control Module: Initial Inspection and Diagnostic Overview
Basic Knowledge Requirements
Basic Knowledge Required
You must be familiar with some of the basics to use this section of the database. They will help you to follow diagnostic procedures in this section.
Basic Electrical Circuits
You should understand basic electricity and know the meaning of voltage (volts), current (amps), and resistance (ohms). You should understand what
happens in a circuit with an open or a shorted wire and you should be able to identify a shorted or open circuit using a DMM. You should be able to read
and understand a wiring diagram.
Use Of Digital Multimeter (DMM)
You should be familiar with the Digital Multimeter (DMM), particularly essential tool J 39200. You should be able to use the meter to measure voltage
(volts), resistance (ohms), current (amps), capacitance (farads), intermittents (min/max) and frequency (Hertz).
Use Of Circuit Testing Tools
You should only use a test lamp when a diagnostic procedure refers to it's use. You should know how to use fused jumper wires to test components and
allow DMM readings without damaging terminals. You should know how to use Connector Test Adapter Kit, J 35616 and use it whenever diagnostic
procedures call for front probing any connector.
Diagnosing Intermittents
DIAGNOSIS DESCRIPTION
Most tables have one result which reads FAULT NOT PRESENT. This means that the conditions that were present when the DTC set are no longer
there. This does not mean that the problem is fixed, it simply means that the problem is intermittent. The problem was present but is not present now.
The problem is likely to return in the future so it should be diagnosed and repaired if at all possible. The only way to diagnose a problem that is not
present is to gather information from the time when the DTC was set. This can be done in two ways; through snapshot data and driver observations.
DIAGNOSIS PROCEDURE
Snapshot data whether Freeze Frame, Failure Records or scan tool snapshot, can be used to check data parameters to see if they fall within normal
operating range. For example, a snapshot MAP parameter value of 100 while the engine was idling is not normal and would indicate that the MAP sensor
voltage went high either due to an open in the 5 volt return or a short to voltage on the sensor signal circuit. Driver observations may give additional
information about the system or area of the car that should be checked for an intermittent. For example, while diagnosing an intermittent DTC P0550,
you find out the driver noticed that the SERVICE VEHICLE SOON message only comes on after an extended wide open throttle maneuver. This would
lead you to check the wiring harness that carries the power steering pressure switch circuit underhood, because it is likely that powertrain movement
(during WOT) is stretching the harness, causing an open circuit. This kind of information, while not airtight, may be very helpful in diagnosing
intermittent conditions. Besides, it may be the only information you can get about a failure and the only chance to find the cause of an intermittent.
DTC Tables
DTC TABLE OVERVIEW
When diagnosing this powertrain, you will almost certainly need to use the diagnostic procedures in this or other powertrain sections. These diagnostic
procedures are mostly in the form of tables. At the beginning of each DTC will be a circuit diagram, descriptions and notes about the condition or DTC
diagnosed in the table. Reading this Diagnostic Support Information will help you understand the DTC or condition and what the table is trying to
accomplish. Below are explanations of the diagnostic support information and tables for DTCs.
CIRCUIT DIAGRAM
The circuit diagram of the diagnostic support information will show the circuits and components involved in setting the DTC. This diagram may be used
as a reference when circuit checks are required in the table. If more detailed circuit information is required, the Engine Controls Electrical Schematic
Diagrams may be referenced.
CIRCUIT DESCRIPTION
The circuit description explains the sensor and/or circuits involved in setting the DTC. It also gives a brief description of when the DTC is set.
CONDITIONS FOR RUNNING THE DTC
The running conditions are the conditions that must be met before the PCM will test for a failure. These conditions are generally set up so that an input
